Gaseous fuels, such as butane and propane, have found a wide acceptance in household and recreational vehicle use. Such fuels are commonly used in association with gas grills, gas lamps, gas heaters, gas cutting torches, and other similar devices. When using such devices, an individual obtains a pressurized gas vessel or cylinder and then connects the vessel or cylinder to a gas consuming device. Typically, the gas consuming device operates at a pressure less than the gas pressure in the pressurized gas vessel or cylinder. As a result, a pressure regulator is mounted downstream of the valve on the pressurized gas vessel or cylinder to reduce the pressure of gas flowing through the valve and into the gas consuming device.
Presently, various safety regulations exist concerning the operation of the valve on the pressurized gas vessel or cylinder. As a result, several attempts have been made to minimize the escape or loss of gas when a gas consuming device is connected to and/or disconnected from the pressurized gas vessel or cylinder. In addition, gas escape or loss also occurs during the refilling of the gas vessel or cylinder. The most common cylinder valve insert is disclosed in U.S. Pat. No. 5,330,155 to Lechner, issued on Jul. 19,1994. Another cylinder valve insert is disclosed in U.S. Pat. No. 5,553,638 to Home, issued on Sep. 10, 1996. Still another cylinder valve insert is disclosed in U.S. Pat. No. 5,582,201 to Lee, issued on Dec. 10,1996. These three patents are incorporated herein by reference. These three cylinder valve inserts reduce the amount of gas escape or loss when a male connector is connected to the valve on the gas vessel or cylinder. However, these valve inserts still result in some gas escape or loss, especially after a male connector has been connected and disconnected several times from the gas vessel or cylinder.
The valve inserts of Lechner '155, Home '638 and Lee '201 are designed to be mounted to a standard cylinder valve. Each valve insert includes a tubular body, a valve member and a seal mounted to the valve member. The valve member includes a docking member designed to form a seal with a nipple of a standard connection fitting. The valve member is biased by a valve member spring thereby causing the valve member to resist movement when the nipple contacts the docking member. The valve member laterally moves in the tubular body as the nipple is further inserted into the tubular body. The lateral movement of the valve member causes the seal to move from a closed to an opened position thereby allowing gas to flow between the connection fitting and the cylinder valve.
Home '638 is directed to an improvement over Lechner '155. Home '638 discloses a tubular member having L-shaped notches designed to mate with a wrench. The L-shaped notches are designed to simplify the insertion of the tubular body into the cylinder valve. Home '638 also discloses that the valve member includes an abutment surface for engagement with a modified POL nipple. The modified POL nipple engages the docking member on the valve member in a manner to reduce gas from leaking between the POL nipple and the valve member. Home '638 discloses that the modifications to the valve member and the POL nipple overcome a problem associated with the valve insert disclosed in Lechner '155. Home '638 discloses that after repeated use of the Lechner valve insert, the strength of the spring may weaken, resulting in the POL nipple not hermetically engaging the docking member prior to the seal moving to an opened position.
Although the arrangement disclosed in Home '638 may overcome a design shortcoming of Lechner '155, the redesigned valve insert of Home '638 has its own shortcomings. The modified POL nipple is designed to contact and abut a surface on the valve member to cause the valve member to move laterally. Prior to the valve member moving, the contoured surfaces of the POL nipple form a seal with the docking member on the valve member.
Lee '201 discloses a valve insert that is similar to the valve insert of Lechner '155 and Home '638. The valve insert has a spring positioned on the end of the seal instead of between the tubular body and valve member as shown in Lechner '155 and Home '638.
All these valve inserts initially function in their desired manner. However, after repeated connection and disconnection of the nipple from the valve member, the movement of the valve member in the tubular member of the valve insert can become impaired. The seals between the valve member and the tubular member can become worn thereby impairing the movement of the valve member in the tubular member. This impaired movement can cause the valve member to stick in the opened position and/or cause the seal between the nipple and the docking member to be prematurely compromised when the nipple is withdrawn from the valve member, thereby causing a gas leak. A lubricant can be inserted between the valve member and the tubular member to reduce wear of the seal and inhibit sticking of the valve member. However, after repeated connection and disconnection, the lubricant is wiped off regions between the valve member and the tubular member. This wiping of the lubricant results in the valve member being susceptible to sticking in these wiped regions. Dirt and other foreign material can also impair the movement of the valve member in the tubular member by becoming wedged between the valve member and tubular member.
In view of the disadvantages of present valve inserts, there is a continued demand for a valve insert that ensures adequate sealing with a separable male connection and that minimizes the loss or escape of gaseous fuel when the cylinder valve is disconnected and re-connected to the male connection.